Enhanced Lithium-ion/Sodium-ion Battery Performances Using Chrysanthemum Flower-like NiO-CoO Anode: Insights into Li+/Na+ Charge Storage Mechanism

In the present work, a chrysanthemum flower-like nickel oxide-cobalt oxide (NiO-CoO) nanohybrid was designed hydrothermally to function as an anode for both lithium-ion and sodium-ion batteries (LIB/SIB). The crystal structure, chemical composition and surface properties of the synthesized NiO-CoO nanohybrid were analyzed using various characterization methods. The lithium and sodium-ion charge-transfer characteristics of the NiO-CoO nano hybrid electrode were evaluated through cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). The LIB half-cell containing the NiO-CoO hybrid anode exhibited an excellent specific capacity of 739 mA h g^-1 at 0.1C-rate. Additionally, SIB performance was also investigated, delivering 340 mA h g^-1 of specific capacity at 0.1C-rate. Interestingly, a full-cell (NiO-CoO|1M LiPF₆|LiCoO₂) was assembled for the first time, employing the NiO-CoO nano hybrid as the anode for the LIB. Further the full cell LIB was presented for real-time applications such as powering commercial LED bulbs and a temperature sensor. The fabricated full-cell sustained illumination for over 5 hours with a green LED bulb on a single charge. The fascinating flower-like morphology of the NiO-CoO hybrid offered short diffusion path, improved electrolyte contacts and effective conversion/re-conversion reactions which in turn led to high charge storage.